1 /*
2 * This file is part of Waarp Project (named also Waarp or GG).
3 *
4 * Copyright (c) 2019, Waarp SAS, and individual contributors by the @author
5 * tags. See the COPYRIGHT.txt in the distribution for a full listing of
6 * individual contributors.
7 *
8 * All Waarp Project is free software: you can redistribute it and/or
9 * modify it under the terms of the GNU General Public License as published by
10 * the Free Software Foundation, either version 3 of the License, or (at your
11 * option) any later version.
12 *
13 * Waarp is distributed in the hope that it will be useful, but WITHOUT ANY
14 * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
15 * A PARTICULAR PURPOSE. See the GNU General Public License for more details.
16 *
17 * You should have received a copy of the GNU General Public License along with
18 * Waarp . If not, see <http://www.gnu.org/licenses/>.
19 */
20 package org.waarp.common.lru;
21
22 /**
23 * @author Damian Momot
24 */
25 class StrongReferenceCacheEntry<V> implements InterfaceLruCacheEntry<V> {
26 private final V value;
27
28 private long expirationTime;
29
30 /**
31 * Creates StrongReferencyCacheEntry with desired ttl
32 *
33 * @param value
34 * @param ttl time to live in milliseconds
35 *
36 * @throws IllegalArgumentException if ttl is not positive
37 */
38 StrongReferenceCacheEntry(final V value, final long ttl) {
39 if (ttl <= 0) {
40 throw new IllegalArgumentException("ttl must be positive");
41 }
42
43 this.value = value;
44 expirationTime = System.currentTimeMillis() + ttl;
45 }
46
47 /**
48 * Returns value if entry is valid, null otherwise.
49 * <p>
50 * Entry is invalid if it's expired
51 *
52 * @return value if entry is valid
53 */
54 @Override
55 public final V getValue() {
56 if (System.currentTimeMillis() > expirationTime) {
57 return null;
58 } else {
59 return value;
60 }
61 }
62
63 @Override
64 public final boolean isStillValid(final long timeRef) {
65 return timeRef <= expirationTime;
66 }
67
68 @Override
69 public final boolean resetTime(final long ttl) {
70 expirationTime = System.currentTimeMillis() + ttl;
71 return true;
72 }
73 }